Agreed, but I doubt that the difference in # of AZ and Moderna/Pfizer doses administered is off by too many orders of magnitude [edit : on second thought, could

Agreed, but I doubt that the difference in # of AZ and Moderna/Pfizer doses administered is off by too many orders of magnitude [edit : on second thought, could be off by a factor of 10]. The central issue in my mind is the difference in populations since Americans have predominantly received Pfizer/Moderna while Brits have predominantly received AZ. Its possible that Brits have an intrinsically higher clot risk with the AZ preparation than Americans do with the Pfizer/Moderna vaccines (although, the J&J clots in the US certainly questions this idea too).